How to Care for Freshwater Invertebrates – Snails, Crayfish, Shrimp, and Clams!

Invertebrates are a major part of the saltwater hobby. But freshwater aquarists often feel as though the options are more limited. And it’s true: you won’t find nearly the variety of intensely colored and strange choices that the ocean provides.

But there are plenty of freshwater invertebrates that are interesting in their own way! Many are as active and engaging a pet as any fish and some grow quite large! Let’s take a closer look at what invertebrates have to offer freshwater aquarists!

General Invertebrate Care Tips

Invertebrates are a diverse group of animals related only by their shared lack of a backbone. But something that they all have in common is that on average they tend to be much more sensitive than fish to pollution and waste products.

Water Conditions for Invertebrates

Ammonia, nitrite, and nitrate are all more of an issue when keeping invertebrates in your aquarium. So you will need to be much more particular about performing regular water changes and keeping up with filter maintenance.

Worse, when an invertebrate dies they tend to rot very quickly, which can cause nitrogenous waste levels to spike very fast. A dead snail can sometimes look just like a live one that has retreated into its shell. This means days can go by where deadly ammonia is being constantly released, slowly poisoning your aquarium.

It’s not fun but if you suspect you have a dead snail or clam, take a moment to smell it. If it smells rotten then you know it has passed away.

Water hardness and pH should also be carefully monitored. With few exceptions, invertebrates need slight to moderate water hardness and alkalinity. These dissolved minerals are what invertebrates use to build their shells and exoskeletons. Keeping them in soft, acidic water can lead to pits and wear forming, weakening their shells and eventually killing them.

Types of Freshwater Snails

There are literally thousands of freshwater snails to be found in the aquarium trade. But these are some of the most common and easiest to keep for beginning aquarists!

Nerite Snails

Of the many types of freshwater snails found in the hobby, nerite snails are probably my favorites. There are a number of species, including the Zebra Nerite and the Horned Nerite that are quite beautiful. Others, such as the Olive Nerite, are more drab.

Nerite snails are some of the best algae eaters you will ever find. They eat almost every kind of algae. While they love green algae, they will also eat brown algae, which few creatures will touch. And even staghorn and black beard algae, which even fewer animals will eat since it’s actively poisonous!

Ramshorn Snails

Of all the freshwater snails out there ramshorn snails are the kind most feared by aquarium keepers. They are excellent at eating leftover food, detritus, and algae. They stay small, are very active, and entirely peaceful as well.

But ramshorn snails do have the tendency to explode in population very quickly. So much so that it’s nearly impossible to get rid of them unless you drain and dry a tank and start over. The eggs sometimes come attached to live plants as well. So make sure that you really, really love these snails before adding them to your aquarium!

Mystery Snails

Mystery snails are sometimes sold as Apple Snails due to the sheer size of an adult snail. They are also algae eaters and detritivores but will sometimes eat soft plants if they run out of food. Decaying plant leaves are also a favorite of theirs, helping live plants remain healthy.

Besides yellow they also come in black, blue, and red. But they are the same species with different names.

Assassin Snails

Assassin snails are slowly becoming more popular and are easy to find in specialty aquarium stores. Their name is rather dramatic considering how small and retiring they are. Assassin snails spend a lot of time buried in the substrate, hiding until they smell something tasty nearby. But they do live up to their name by hunting and feeding on other snails.

 Assassin snails feed on other snails, especially small species like ramshorn snails. This makes them popular for aquarists looking to get their snail population under control. Once they run out of other snails to eat you can feed them on pieces of shrimp, fish, and other meaty items.

Caring for Freshwater Snails

Feeding Freshwater Snails

Freshwater snails are extremely easy to feed because they will eat just about anything. Algae, decaying plants, fish poop, leftover flakes…If it’s organic a snail will eat it. By eating these leftovers they remove extra nitrogen from it, lowering the ammonia produced once they make their own poop.

Assassin snails are the one exception; being predators they need to be fed other snails or meat to survive. But the rest will thrive on leftovers and algae. Once your snails eat up all of the available leftovers you can clip lightly boiled vegetables to the glass, where your snails will find it during the night and strip it clean!

Tank Mates 

Tank mates for snails should be chosen fairly carefully. Large fish may pick at them and some, including goldfish and larger catfish, may simply swallow them whole. Most small fish will leave a snail alone. But sometimes the long, trailing antenna that they use to smell their environment may be too tempting for barbs and other nippy fish to ignore.

Snail Eggs and Population Control

Something to be aware of is how easily snails can get out of control. Nerite snails don’t have this problem because their eggs require brackish to full saltwater to develop properly. These are the best snails if you don’t want babies around.

Ramshorn snails tend to breed uncontrollably. And mystery snails will readily breed but are easy to keep under control. They lay their eggs in a large hard mass just above the waterline. You can simply scrape away the eggs before they hatch if you don’t want any extra!

Types of Freshwater Shrimp

Ghost Shrimp

Ghost shrimp are the least expensive and easiest freshwater shrimp to find because they are often sold as feeders for cichlids and other large fish. They make excellent pets – but live only a year to two years at most.

They get their name from their see-through bodies. Ghost shrimp feed on leftover flakes, algae, and detritus. But in an aquarium with other small animals they will often swim freely in open water in their search for food, and even come to the surface to try and grab flakes!

Red Cherry Shrimp

Red cherry shrimp are the most popular captive breed of Neocaridina davidi, a normally small, brownish shrimp found in Taiwan. They are sold in a rainbow of colors and patterns but share identical care needs.

Red cherry shrimp are very hardy but should be kept with small fish like Neon Tetras and Guppies. They may live alongside an adult betta but the young they produce may be eaten by a hungry betta.

 Asian Bee Shrimp

Asian bee shrimp are another Taiwanese species of freshwater shrimp that’s a little more complicated to care for. For one, they actually prefer neutral water conditions. They are also more sensitive to pollutants and harder to feed and breed. But many aquarists keep shrimp-only tanks dedicated to these expensive but beautiful little invertebrates!

Bamboo Shrimp

If you prefer a larger, showier species then the bamboo shrimp is worth getting to know better! Unlike other shrimp these are filter feeders that hold their feathery arms out into the current to pluck floating bits of food. They need to be fed baby brine shrimp, crushed flakes, and other items. Growing up to 3 inches long, they have a camouflage pattern that’s fascinating in its own right!

Caring for Freshwater Shrimp

Feeding

With the exception of the bamboo shrimp, most freshwater shrimp are scavengers and omnivorous. They love to snatch up leftover flakes and pellets, squabbling for their share and running off with tasty bits.

Some shrimp will also eat algae, especially the Amano Shrimp. But most prefer softer items. Cherry and bee shrimp also graze on the bacterial biofilm that forms on hard surfaces like aquarium glass, rocks, and driftwood. So it’s better to keep these kinds of shrimp in fully mature tanks that have plenty of slimy biofilm for them to eat.

Tank Mates

Unfortunately shrimp are often difficult to keep with fish because they are a natural food source for so many species. Even seemingly peaceful fish may try snapping at a dwarf shrimp, hoping to snap off a delicate leg.

It’s best to stick to small fish like tetras, cherry barbs, livebearers, Otocinclus, and Corydoras. Nano fish (fish smaller than 1 inch) are an even better combination since they are less intimidating to the tiny crustaceans. Popular nano fish include chili rasboras and galaxy rasboras!

Types of Freshwater Crayfish

Crayfish are crustaceans like shrimp so they are naturally very similar in appearance. However they are much larger, growing to be several inches in length, and tend to be very aggressive.

Louisiana Red/American Crayfish

The American crayfish is by far the most commonly bred species in the world. They are often raised for food but sometimes find their way into the pet trade. Besides red they also come in blue and a stunning leucistic (white) color morph.

American crayfish are hardy and amphibious, able to live out of water when kept wet for days at a time. They are also voracious predators, making them hard to keep alongside most fish since they can easily overpower and eat their tank mates.

Dwarf Crayfish

Dwarf crayfish, on the other hand, make better residents for most community tanks. These smaller crustaceans rarely grow beyond 1 inch in length. Their claws are tiny as well, making them no threat except maybe to a tiny fish that’s too sick to escape. So long as they are well fed they can even be kept alongside dwarf shrimp

Freshwater Lobster

Freshwater lobsters (genus Cherax) are found exclusively in Papua New Guinea and Australia but are becoming more popular in the aquarium trade. These are especially large crayfish; some growing nearly a foot long.

Freshwater lobsters are actually a little easier to keep alongside certain fish due to their size and dietary habits. They are still opportunists but have a larger appetite for fresh vegetables like spinach and peas.

They can easily be kept alongside surface dwelling fish like hatchetfish and rainbowfish, which almost never go near the bottom of the tank. These lobsters are also burrowers and should have a substrate deep enough to hide themselves in.

Their burrowing habit and size makes it easier to keep alongside large fish like cichlid and catfish. They may still be in danger of being eaten, especially after moulting, when their shells are still soft. But so long as they have a burrow, your freshwater lobster will hide during this time until their new shell fully hardens.

Caring for Freshwater Crayfish

Feeding Freshwater Crayfish

Feeding a crayfish is very easy to do because they are almost as omnivorous as us humans. Animal or plant, alive or dead, so long as it’s organic, a crayfish will eat it. Flakes, pellets, peas, lettuce, fish, shrimp, meat…They are willing to try anything that looks edible and will sample things that aren’t. Which is part of the problem with keeping them with other animals.

Tank Mates

You can get a food feel for their temperament just by picking one up. Crayfish immediately spread their arms out, ready to pinch anything, no matter how much larger it is.

American crayfish are both constantly hungry and very ill-tempered, a bad combination. Any fish that’s smaller than them will end up a meal if they get caught. People sometimes say “well, just keep fast swimming fish that live near the surface,” not remembering that all fish sleep and some will get sick or swim the wrong direction. It only takes one misstep to end up in the claws of a hungry crayfish.

But larger fish can also be problematic because they may see the crayfish as a meal instead. It’s best to keep crayfish in their own tank. Dwarf crayfish, on the other hand, are good community tank residents since they are the same size as everything else. They can live alongside other invertebrates and most freshwater community fish!

Types of Freshwater Clams

Asian Golden Clam

The Asian golden clam is pretty much the only species that’s commonly found in the aquarium trade. Sometimes you can find freshwater mussels but they are both very rare and mostly endangered (and therefore illegal to own).

These small clams are farm raised mostly for export to Asian grocery stores around the world. They grow no larger than 1 inch and have an attractive buttery yellow hue to their shells. Like all clams they are entirely peaceful, spending their entire lives slowly filtering water through their bodies for plankton.

Caring for Freshwater Clams

Aquarium Design for Freshwater Clams

Of all the invertebrates I’m covering here, freshwater clams are by far the most difficult to care for. You really need to think carefully on setting up a tank for them because they have exacting care needs. And should one die you’ll have a slow release ammonia bomb in your gravel that you may never find.

Clams prefer softer substrates like sand and small grained gravel. Larger gravel grains are too difficult for them to properly bury themselves in and should be avoided. Live plants may occasionally be disturbed by their digging. But I still recommend keeping them in planted tanks because plants help grow the microorganisms that clams need to survive. Without them it’s nearly impossible to keep a clam healthy for very long.

Feeding

Feeding a freshwater clam is also challenging. They are filter feeders by nature and continually pull in fresh water through a small siphon while expelling it from another. Clams strain zooplankton and phytoplankton, including green water algae, from the water.

In mature tanks with loads of plants, a soil bottom, and other sources of biomass, you may have enough floating plankton to feed a single clam. But avoid keeping several unless you know for sure that the tank can sustain a healthy clam long-term.

Clams also make great additions to aquariums struggling with green water algae since the pea soup fog is like a buffet for them!

Tank Mates

Freshwater clams are entirely peaceful and simply want to be left alone. In the right conditions they will usually only allow the edge of their shells and siphons to be exposed in order to breathe and feed. So they aren’t animals you buy because they are active; you buy a freshwater clam for the challenge of keeping one alive!

Wrapping Things Up

Freshwater invertebrates aren’t as numerous as their saltwater cousins, which you might find in a nano reef tank. In freshwater environments, there aren’t any corals, sponges, or sea anemones to choose from. However, there are still plenty of intriguing options; shrimp, crayfish, snails, and clams all add biodiversity that goes beyond fish and plants!

Just like maintaining a nano reef tank, caring for freshwater invertebrates also requires mindfulness of their different feeding strategies and needs for extra-clean water. With the right attention and care, you’ll go far in creating a thriving aquatic ecosystem, whether it’s a freshwater setting or a compact, vibrant nano reef tank.